The ABCD of CDMA
By: Sachin Kalbag, December 28,2002
mid-day.com
What exactly is the big deal with CDMA?
Simply put, CDMA stands for Code Division Multiple Access, one way of cellular phone communication. Others include GSM (Global System for Mobile Communication), TDMA (Time Division Multiple Access) and FDMA (Frequency Division Multiple Access) – three others that are used across the world.
What does this mean to you and me?
For you and me, CDMA changes the way our voice is sent to the person on the other side. Because of the way it assembles our voice (and that of several other people using the same service) in the same frequency, CDMA increases the clarity of voice. You can also receive calls when signals are weak.
OK, now try to visualise….
Until now, a majority of Indian cellphone users were on the GSM (Global System for Mobile Communication) platform. To visualise this system, imagine a locked room where you and your friend are talking to each other. Hence there is no interference.
In CDMA, imagine the same locked room with several persons talking in unique languages with no one pair understanding what language the other pairs are talking. In short, each of our conversations is coded (hence the name Code Division), and the code is then reassembled by the time our voice reaches the other person from multiple places (hence the name Multiple Access).
So, why is it in the news suddenly?
Because, India’s largest private sector company Reliance will today launch IndiaMobile, India’s most ambitious telecom network. Its phones will work only in the Wireless in Local Loop (WLL) model using CDMA technology. This means you phone will work only within a given area specified by the service provider. But with a tariff of just 40 paise per minute at a flat rate, it certainly is India’s most competitive pricing for a telecom product yet.
Is CDMA superior? What are the pros and cons?
The pros
CDMA systems lower cost of operations and increase call quality.
CDMA phones (like the ones Reliance Infocom will provide – Samsung Java W XBS and LG RD 2030) are geared to work at lower power levels. This increases your chances of receiving a call even if the signals are weak.
CDMA phones are multimedia enabled. So, apart from text and pictures, you can also listen to audio and video files.
CDMA phones also give you multiple-party conferencing.
The cons
The service will work only in a limited area. Hence the name Wireless in Local Loop (WLL).
Technically, the price for scrambling and unscrambling of codes mentioned above is expensive. Hence, CDMA phones tend to be more expensive than their GSM counterparts. A counterpart to a Rs 7000 GSM phone can easily cost upwards of Rs 10,000 CDMA phone. Premium handsets with colour screens cost a minimum of Rs 17,000.
But Reliance is overcoming that disadvantage by offering phones free along with a particular package. For instance, in the Dhirubhai Ambani Pioneer scheme, the subscriber has to pay Rs 3000 as membership charges and Rs 600 per month telephony charges. He will get one mobile phone free, besides free incoming calls, voice mail, call conferencing, STD/ISD lock and even SMS. |
